Density and Viscosity of Linear Siloxanes and Their Mixtures

Abstract

Density and viscosity measurements are performed for ethanol, water, hexamethyldisiloxane (MM), octamethyltrisiloxane (MDM), decamethyltetrasiloxane (MD2M), and their mixtures (ethanol/water, MM/MDM, MM/MD2M, MDM/MD2M) at 100 kPa at different temperatures (293–423 K) and mixture compositions. To measure the density and viscosity, an IMETER measuring system with a combined dynamic and static force measurement method, a density meter with an oscillating U-tube measuring method, and a rheometer with a double-gap measuring system were used. The experimentally determined data for the pure substances show a very good agreement with literature data. However, there is a strong deviation of the mixture viscosity between max 7% for MM/MDM and 31% for MM/MD2M compared to Refprop v.10.0. In order to enable an improvement in the calculation of the density and viscosity for the mixtures, specific parameters for the Jouyban–Acree model are developed for all mixtures and thereby, a better description of the density and viscosity for the mixtures could be achieved.